Units of the type described in the introduction are used for example in the furniture and kitchen construction sector to provide carcass parts with drill holes (for example for dowels), grooves (for example for rear walls), or the like. FIG. 3 shows the structure of a unit known to the applicant in a schematic top view. The unit comprises a plurality of vertical drill spindles, a plurality of horizontal drill spindles and a saw. In this regard, the saw is integrated with a unit with four horizontal drill spindles and this unit can be rotated about a vertical axis (perpendicular to the plane of projection in FIG. 3) in order to permit horizontal drilling work and sawing work in several directions and endow the unit with sufficient flexibility.
In order in addition also to permit vertical drilling work in several directions, the unit comprises two rows of vertical drill spindles disposed orthogonally to each other. This disposal requires a high number of vertical drill spindles resulting in a complex structure and a high weight and requires a powerful drive.
There is also a commercially available “Alberti-Polar” CNC-machining centre in which a complete set of units can be rotated about 360.